chasni

Hi

I bought a 4Ch Dynam I can fly RC Plane. This is my first RC plane.

1 - I want to fly it straight with controls in neutral position. Can some1 help me with adjusting the control throws ? What should be the proper control throw for this plane?

2- I have inserted the push rods in the second hole of the horn as given in the manual. But when I try to run the plane on the ground, It automatically starts steering left after some distance. Even though my rudder is perfectly aligned with the vertical stabliser. Is this usual ??
But I feel the vertical stabliser is little bit curved (not vertical perfectly)

3- I m also getting unequal throws on the rudder. How to correct this ?

4- I am getting less elevator movement in the upward direction because its movemebt is blocked by the rudder. Is this supposed to happen ?

Plz help me..

CGRetired

My Feedback: (1)

The first thing you have to do is make everything straight. That means no up or down in the elevator and ailerons, and no left or right in the rudder. Straight.

How I do this is disconnect the linkage, then center the servos using the transmitter. If you have clevis's on there, slide a piece of rubber tubing over the rod. You will use these later. Make sure all the trims and sticks are in the absolute center position. Some radios have a little screen with a position indicator for each stick. If yours does, then center all using that indicator.

Next, insure that the servos are centered, meaning the control arms on each of the servos is in the center position. If not, you can remove the servo arm and rotate it 90 degrees (using the four arm servo arms). On one of the rotations, the servo arm will be straight and perpendicular with the direction of movement.

I then use a couple of paint stirring sticks (those you get free at the paint store that are about a foot long, about an inch wide, and about 1/8 inch thick. I use that to clamp the control surfaces straight with the stab/wing. I put a stick on each side of the surface then use a small clamp to hold it in place. This makes the control surface as straight with the wing or stab as possible.

With that done, you can now attach the linkage to the serovs, turning the clevis until the linkage slides easily into the holes on the servo arms without moving it (this is also done with the transmitter on to hold the servo in place).

When done, secure the clevis's or the rods into place using the little servo rod keepers, or those pieces of rubber tubing wrapped around teh clevis's before you started (slide them over the clevis to hold them closed).

Remove the clamps and the wood paint stiring sticks.

Move your sticks and all should be centered.

Now, once you fly the thing, all bets are off because you will most likely have to trim the plane for straight and level flight. We all have to do that, and usually on the first flight of each day, but that's just part of the hobby.

Good luck.

CGr.

CGRetired

My Feedback: (1)

In addition, for further info on your original post, you will probably never get it to steer straight with mechanical adjustments. That comes with trim AFTER you do the correct centering adjustments. But, you can get it as close as possible using the method I've outlined.

Movement blocked by the rudder? In the center positions? Doesn't make sense, or you misadjusted things. Again, follow the above to center all and try it again. Your servo centering is a key factor here.

CGr.

stevenmax50

My Feedback: (1)

WOW.  The paint stick idea is awesome.  Ive always just eyeballed it.  Since I am almost at that point on my Tiger I will definatlt try the paint sticks.  Thanks!

chasni

I have made everything straight as u described and have even centered the servos but when I try to run the plane on the ground, It automatically starts steering left after some distance even when the stick is in neutral position and rudder is aligned.

My elevator is not blocked by the rudder in the centre position.  It gets blocked by the rudder when i try to move it up. Due to this blockage i am getting unequal elevator movement ( elevator movement in upward direction is less than downward direction).

chasni

Here the the pics -

opjose

Most planes, particularly "tail draggers" ( with the small wheel on the tail ) tend to yaw left as you describe as you run the engine up at takeoff.

It is up to the pilot to deal with it. Welcome to RC!

In many cases those seemingly flawless takeoffs are demonstration of pilot skill.

There are things you can do to minimize left yaw.

- Toe in the front wheels so they point a bit towards the propeller as viewed from above.
- Once you have set the toe in, push the plane on the ground and assure it runs straight...
- Pull or bend the tail wheel out/down so that the tail of the plane sit's higher.
- Make sure the tail wheel lines up with the rudder.
- Add a small amount of right rudder ( once you've done the above ) so when you push the plane on the ground it tends to run a bit towards the right.
- Compensate for left yaw, by getting into the habit of moving the rudder slightly right as you push the throttle up.

Also DO NOT pull back on the elevator at takeoff. Instead let the plane build up speed and seemingly take off on it's own.

If you pull back, you'll send the plane into a stall, that coupled with the yaw, will cause ot to roll over and head down nose first. This is an often seen newbie mistake.

goirish

It looks like the control horn on the rudder is not on the hinge line. could be why you more throw one way and not so much the other.

chasni

@ opjose : Do i need to toe in both the front wheels or the one on the left side only?
As I have already glued the back wheel. Can i try anything else ?

Plz look at the pictures. Elevator movement is restricted by the rudder. Is this suppose to happen ?

I cannot remove the rudder and elevator servos to centre them as they were already glued when i received them. I have tried to maintain equal control throws but unable to get them. Is this the flaw in the push-pill system used to control these surfaces ??

opjose

Toe-in is adjusted on the front wheels.

With wire gear, you just bend them BOTH in equally.

As far as the elevator....

Move the elevator fully up or down and see where the rudder hits it ( as in your photo ), you can cut a small triangular area off the bottom of the control surface on the rudder, to let the elevator move up more.

As long as you get adecuate travel in each rudder direction, you do not have to worry about unequal travel on your foam trainer.

While this is not desireable, the plane is really controlled via the ailerons and elevator and you will not use the rudder very much.

Also yours is not all that bad that you should worry about it. Worry more about making sure the rudder centers, and the tail wheel lines up with the rudder.

BTW: A computer controlled radio let's you fine tune the control surface travel even when there are errors in physical linkages....

However the TX's that come with most ARF's of not of high or advanced quality.

If the RC bug really bites you, you'll want to invest in a good computer controlled TX that will handle a whole fleet of airplanes for you.

chasni

Thanx for the help... I ll try to implement your suggestion tomorrow and will see how it goes for me...

QSR1

I have a Dynam TurboJet
I dont like the throw amount after build on the elevator, I just dont think its enough

12-15mm is what they say, I might have half that.

It is set on inner hole on servo control arm and outer hole on elevator control arm.

Control arm on servo is centered.

Ideas?

JohnBuckner

My Feedback: (1)

chasni the amount of the up elevater throw when it connects with the rudder is all the throw you need and in fact I would reduce the down throw to a similar degree in the transmitter if it has that capability. If not I would use a hole further out on the elevator at the elevator control horn or move the pushrod in to a closer hole at the servo then recenter the neutral.

John